Fig 1: Epithelial/mesenchymal nature of patient CTCs and CDX. CTCs were enriched via ISET filtration from a parallel blood sample to that which generated the CDX. The ISET filter was stained for pan-CK (green), vimentin (blue), CD45 and CD144 (pink), and DAPI (white). (A) Representative images and (B) quantitation of cells classed as epithelial, mixed epithelial/mesenchymal (E/M), and mesenchymal. Also shown is a circulating tumour microemboli (CTM) containing cells of all three phenotypes. *Leucocyte or endothelial cell; scale bar, 10 µm. Quantitation carried out by two independent scorers on two ISET spots, each counting >150 CTCs per spot. Error bars, SEM. (C) Single cells from the ISET filter shown in A classed as a leucocyte/endothelial cell, epithelial CTC, mixed E/M CTC, or a mesenchymal CTC were captured by laser capture microdissection. The PACRG locus, shown by WES to be mutated in the CDX, was Sanger sequenced in DNA extracted from the captured CTCs and green fluorescent cells (leucocytes or endothelial cells), from the patients PBMCs (germline sample), from their primary tumour biopsy and from the passage 2 CDX shown in Figure 1A–C. Highlighted base represents the mutated base. (D) RNAseq was carried out on passage 2 NSCLC CDX tumours and passage 3 CDX from two SCLC CDX models. Expression of EPCAM, KRT8, VIM, S100A4, CD44, and CD24 is displayed as RPKM values. Data represent mean of three independent tumours ± SEM. *P < 0.05; ***P < 0.001 according to two-tailed unpaired t-test. (E) Tumours analysed in D were stained for expression of pan-CK, vimentin, and CD44 (scale bar, 50 µm).